A shower arm consisting of two telescopically composed cylindrical tubes has become known in the state of the art from GB-2,172,802. If pressure is exerted on the cylinder by warm wash water, the foremost tube and the middle tube telescopically extend against the restoring force of a spring. When the pressure subsides, the cylinder drops back into the resting position. This shower arm has the advantage of having a short overall length, but the disadvantage that the shower arm has a complicated design and especially has sliding packings which may lead to disturbances and frequently cause leakage. A shower arm moved with an electric motor has become known from U.S. Pat. 4,570,274. The above-mentioned sealing problems are avoided in this drive, but a relatively expensive electric motor is needed, and it needs to be protected especially from corrosion, and requires corresponding electrical devices. Drives with an electric motor have also become known from DE-A 38,17,904.